1. Field of the Invention
The present invention relates to a composite particulate preparing apparatus and method, by which an adhering material is made to adhere to particulates so as to form composite particulates.
2. Description of the Related Art
A physical vapor deposition method (PVD) or a chemical vapor deposition method (CVD) has heretofore been used as a method for causing an adhering material to adhere to an adhesion substance such as particulates. The CVD method is a method in which an adhering material is made to adhere to the adhesion substrate by a chemical reaction in vapor phase.
The PVD method is a method in which an adhering material is caused to adhere to the adhesion substance by thermal vapor deposition, sputtering, ion plating or the like.
Of the CVD method and the PVD method, an appropriate one is selected depending on a material constituting the adhesion substrate and an adhering material. If the adhesion substance is particulates, the PVD method having a comparatively wide range of selection of the adhering material is used. In particular, the sputtering method is frequently used.
The sputtering method is a method in which an anode and a cathode are arranged in a He or Ar gas atmosphere together with an adhesion substance and an adhering material (target) which are located between the anode and the cathode. In addition, voltage is impressed between both the electrodes, whereby the adhering material is sputtered from the target and made to adhere to the adhesion substance.
If the adhesion substance is particulates, various forms of sputtering apparatuses have been proposed in order to achieve uniform adhesion of the adhering material to the overall particulates. For example, a method is proposed in which composite particulates are prepared by pressing powder to the inner surface of a rotating stage by the centrifugal force caused by rotating the cylindrical stage. (See e.g. Japanese Patent Laid-Open No. 2008-45197.)